The present invention is related to minimizing the operating current of a circuit. More particularly, the present invention is related to a method and system for reducing the operating current of a voltage regulator by periodically disabling the voltage regulator with an oscillator circuit.
Demand for portable electronic devices is increasing each year. Example portable electronic devices include: laptop computers, personal data assistants (PDAs), cellular telephones, and electronic pagers. Most portable electronic devices are powered by batteries. Portable electronic devices place high importance on total weight, size, and battery life for the devices.
Although battery technology has improved over the years, the total weight associated with the portable electronic device is greatly affected by the weight associated with the battery. As current consumption requirements increase, additional or larger batteries are required to supply the additional energy to power the device. Thus, there is always a tradeoff between the weight associated with the battery and the total use time associated with the portable electronic device.
Voltage regulators are often used in portable electronics to maintain the operating voltage at a relatively constant level. Some regulators have a high xe2x80x9cdrop-outxe2x80x9d voltage. A xe2x80x9cdrop-outxe2x80x9d voltage corresponds to the difference between the input supply voltage (or unregulated voltage) and the regulated output voltage. Large drop out voltages result in wasted power, and raise the minimum power supply requirements for the electronic device. A low-drop out regulator (hereinafter referred to as an xe2x80x9cLDO regulatorxe2x80x9d) is a particular type of voltage regulator that is useful in applications where the input supply voltage is relatively close to the desired regulated supply voltage.
A typical LDO regulator (XLDO) is illustrated in FIG. 1. The LDO regulator (XLDO) includes a voltage control circuit (XVC), a transistor (MREG), and two resistors (R1, R2). Voltage control circuit XVC controls transistor MREG via control signal CTL. Resistor R1 and R2 provide a feedback signal (SENSE) that is compared to a reference voltage (VREF) by the voltage control circuit (XVC). The output voltage (VOUT) is provided to a load circuit (ZL). A capacitor (COUT) can be connected in parallel to the load circuit to provide filtering of supply ripple in the output voltage (VOUT).